Fluid-pressure-operated tool.



c Patented Oct. I4, |902.

H. JuHNsoN. -FLUID PRESSURE OPERATED TOOL.

(Application filed Jan. 20, 1902.)

(Nu Model.)

up \w -s n G 1 5 l, N I E Mbegsseqsf zwww i pressure-operated tools,and more particularly UNITED STATES PATENT OEEICE.

CHARLES HARRIS JOHNSON, OF CHICAGO, ILLINOIS.

FLUID-PRESSURE-OPERATED TOOL.

SPECIFICATION forming part of Letters Patent No. 711,425, dated OC'OlOel 14, 1902- Application led January 20, 1902. Serial No. 90,469. (No model.)

T0 @ZZ whom t may concern:

Be it known that I, CHARLES HARRIS JOHN- SON, a citizenof the United States, residing at Chicago,county of Cook, State'ot Illinois, have invented a certain new and useful Improvementin FluidPressure-Operated Tools; and I declare the following to be a'full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying draw ings, which form a part of this specification.

My invention relates in general to fluidto pneumatic hammers of? the valveless type.

In luid-pressure-operated tools as ordinarily constructed the piston delivers a blow upon a snap or the shank of a tool, the initial propulsion of the piston toward the tool being due to the flow of fluid-pressure froml the source of motive-Huid supply, while the final portion of the stroke is due to the expansion of the fluid within the cylinder after it has been cut oft from the source of uidpressure supply. Fluid pressure operated tools have also been constructed heretofore in which impetus is given to the stroke of the piston toward the tool by the expansion of pressure into the working end of the cylinder from a single reservoir, which has been charged during the throw of the piston away from the tool. It is obvious, however, that in a tool so constructed the greatest impetus is given to the piston at the instant the reservoir communicates with the working end of the cylinder and that during the remainder of the stroke of the piston toward the tool the pressure diminishes by expansion into the cylinder.

The primary object of my invention is to produce a luidpressure-operated tool in which the initial stroke of the piston toward the tool is effectedby the admission of pressure from the source of motive fluid, While the piston is given an additional impetus at a plurality of successive points in its stroke.

Afurther object of my invention is to provide a iuid-pressure-operated tool which will be simple in construction and efficient in operation.

My invention, `generally stated, consists in providing a fluid-pressure-operated tool with a plurality of reservoirs which successively discharge into the working end of the cylinder during the stroke of the piston toward the tool.

My invention further consists in a fluidpressure-'operated tool comprising a cylinder, a reciprocating piston therein, and a plurality of reservoirs which are successively charged during the throw of thepiston away from the tool prior to the admission of pressure to the working end of the cylinder and which successively discharge into the cylinder during the stroke of the piston toward the tool.

My invention will be more fully described hereinafter with reference to the accompany- "ing drawings, in which the same is illustrated as embodied in a convenient and practical form, and in which- Figure l is a longitudinal section through a tool embodying my invention, showing the piston delivering a` blow upon the tool; and Fig. 2 is a similar View showing the piston at the beginning of its stroke toward the tool.

The same reference characters are used in the two figures of the drawings to indicate the same parts.

Reference -letter A indicates a cylinder, within which the piston D reciprocates. A handle B is secured to one end of the cylinder in any suitable manner. In the present instance a Iiange B overlaps the end ot' the cylinder and is held in such position by a cap a, which is provided with a screw-threaded tubular portion in engagement with the interior surface of the end of the cylinder. A liangeb, formed on the handle B, is interposed between the head of the cap a and the end of the cylinder A. Any suitable means may be provided for retaining the cap a from rotation with respect to the handle, such means being shown as consisting in a spring-actuated bolt hl, engaging with ratchet-teeth on the rim of the cap a.

A throttle-valve B5 is located within a valveseat B, which is screwed into a tubular ex tension on the handle B and controls ports b5 through the valve-seat.v y l v B4 indicates a coupling to whichfa y'pipe leading from the motive-duid supply is seycured.

B3 indicates a reciprocating spindlewhichl IOO at one end engages the throttle-valve Bland at its other end is engaged by a hand-operated lever B2, pivotally mounted in the handle B.

b3 indicates a passage in the handle B, communicating at one end with a passage controlled by the throttle-valve and its other end in register with a passage a3 in the cylinder A. An annular chamber A3, formed in the cylinder, communicates with the other end of the passage a2. AchamberA5 is provided in the end of the cylinder opposite to the handle B, such chamber communicating with the atmosphere through exhaust-ports a5. A ferrule E is fitted within the end of the cylinder adjacent to the chamber A5, in which a die or snap or the shank of a tool F is located. A plurality of chambers A and A2, preferably annular in form, are provided within the cylinder by enlarging the bore thereof between the supply-chamber A3 and the cap a. A partition d3 separates the supply-chamber A3 from the chamber A2, while a second partition a2 is interposed between the chambers A2 and A. A third partition a is interposed between the chamber A' and the end of the cylinder, within which is located the screwthreaded portion of the cap ct. The chambers A and A2 serve as reservoirs, which are successively charged with pressure from the motive-fluid source during the stroke of the piston away from the tool and before the admission of pressure to the working end of the cylinder. The diameter of the enlarged portion D' of the piston is substantially the same as the bore through the partitions a', a2, and a3, and the length of the enlarged portion D between the shoulder d' and the large end of the piston is slightly greater than the length of each of the reservoirs A2 and A.

The piston D is of a differential type and is provided with a shoulder d', formed between the main portion of the piston and the enlarged end thereof, D. The piston is preferably hollow and provided with ports d, extending from the interior thereof to the outer surface and located adjacent to the end of the piston opposite to the enlarged portion D. rlhe reduced portion of the piston D is ot' such a diameter as to closely fit the inner surface of the portion A4, which extends between the annular chamber A3 and exhaust-chamber A5.

The operation of my improved fluid-pressure-operated tool is as follows: The handlelever B2 is depressed, as indicated in Fig. 2, which through the interposed spindle B3 depresses the throttle-valve B5, so that the latter uncovers the ports b5. Motive duid consequently flows from the source thereof through the coupling B4, thence through the ports b5 to the passage b3, which registers with the passage d3, which in turn communicates with the annular chamber A3. The piston D being in the position indicated in Fig. l, the motive iiuid is exerted upon the shoulder d and causes the piston to move toward the handle, inasmuch as the larger end of the piston and also the cylinderand chambers A and A2 therein are in communication with the atmosphere through the piston, ports rl, the chamber A5, and the ports a5. When in the movement of the piston toward the handle the enlarged portion D passes beyond the partition a2, Huid-pressure is admitted around the reduced portion of the piston into the reservoir A2 and charges the same. A continuation of the movement of the piston toward the handle charges the reservoir A upon the shoulder d', passing beyond the partition a2. The piston continues in its stroke toward the handle B until the ports d register with the annular chamber A2, as illustrated in Fig. 2, at which time motive fluid is admitted through the ports d to the interior of the piston and thence to the working end of the cylinder. The greater area of the larger end of the pist0n is consequently subjected to pressure and the piston immediately commences its stroke toward the tool. The communication with the motive iiuid is cut o as soon as the ports d pass out of register with the annular chamber A3, which occurs before the enlarged end D' of wthe piston passes beyond the partition a. As soon as the partition a is passed by the pistou the pressure which has been stored in the reservoir, consisting in the chamber A', discharges into the working end of the cylinder and adds impetus to the stroke of the piston. When the piston passes beyond the partition a2, the reservoir A2 communicates with the working end of the cylinder and adds impetus to the stroke of the piston by the expansion of the Huid-pressure which has been stored therein. Upon the ports d being uncovered by the chamber A5 the working end of the cylinder exhausts through the ports ai and the stroke of the piston in the opposite direction-namely, toward the handle-commences, by reason of the motive fluid being exerted upon the shoulder d'.

From the foregoing description it will be observed that the stroke of the piston toward the tool is commenced by motive liuid admitted through the piston to the working end of the cylinder, while the stroke of the piston during that portion of its travel when the ports d are closed by the restricted interior surface A4 of the cylinder is effected not merely by the expansion of the motive iiuid which has been admitted directly to the working end of the cylinder from the supply, but also by the expansion into the cylinder successively of the motive iiuid which has been charged in the plurality of reservoirs, preferably prior to the admission of the motive iuid from the supply to the cylinder. By successively connecting the reservoirs with the supply during the interval of time occupied by the shoulder d of the piston passing from the partition a3 to the end of the pistonstroke the reservoirs are completely charged directly from the supply and only discharge into the working end of the cylinder after the stroke of the piston toward the tool has commenced by the admission of motive Huid ICO ' ton and is not diminished by expansion from the working end of the cylinder into the reservoirs.

It is obvious that a. greater number of reservoirs than two may, if desired, be utilized 4 to add impetus to the stroke of the piston toward the tool by successively discharging into the working end of the cylinder;

While I have described more or less precisely theM details of construction, I do not wish to -be understood as limiting myself thereto, as I contemplate changes in form, the proportion of parts, and the substitution of equivalents as circumstances may suggest or render expedient Without departing from the spirit of my invention.

Having now fully described my invention, what I claim as new, and desire to secure byl Letters Patent, is

l. In a fluid-pressure-operated tool, the combination with a cylinder, of a reciprocating piston therein, means for imparting an initial movement to said piston toward the tool, and means for adding impetus -to the piston at a plurality of successive points in.

its stroke.

2. In a fluid-pressure-operated tool, the

combination with a cylinder, of a reciprocating `piston therein, means for admitting fluidpressure to the working end of the cylinder to impart an initial movement to said piston, a plurality of reservoirs, and means for successively discharging said reservoirs into the working end of the cylinder.

3. In a iiuid-pressure-operated tool, the

combination with a cylinder, of a reciprocating piston therein, a plurality of reservoirs, means for successively charging said reservoirs during the throw of a piston away from the tool and successively discharging said reservoirs into the working end of the cylinder during the stroke of the piston toward the tool.

4. In a fluid-pressure-operated tool, the combination with a cylinder, of a reciprocating piston therein, means for admitting duidpressure to the working end of the cylinder from a supply source, a plurality of reservoirs, means for successivelycharging said reservoirs during the throw of the piston away from the tool prior to the admission of pressure to the working end of the cylinder and successively discharging said reservoirs into the working end of the cylinder after the motive-fluid supply'has been cut off therefrom.

5. In a uid-pressure-operated tool, the combination with a cylinder, of a reciprocating piston therein, a plurality of reservoirs connected with the fluid-pressure supply by the piston during its throw away from the tool and successively connected with the working end of the cylinder by the piston during its stroke toward the tool.

6. In a fluid-pressure-operated tool, the combination with a cylinder having its bore enlarged to form a plurality of reservoirs, of a reciprocating piston successively connecting said reservoirs with the source of fluidpressure during its throw away from the tool and successively connecting said reservoirs with the working end ofthe cylinder during y its strokev toward the tool. l

7. In affluid-pressure-operated tool, the combination with a cylinder having the bore thereof enlarged to form a supply-chamber and a plurality of reservoirs, of annular partitions between said supply-chamber and the adjacent reservoir and between said reservoirs respectively, a reciprocating piston with-V in said cylinder, and an enlargement on said piston closely engaging said annular partitions and adapted to successively pass beyond the same during the stroke of the piston away voirs in turn with said supply-chamber.

,9o from the tool thereby connecting said reser- 8. In a iluid-pressure-operated tool,'the

combination with a cylinder having the bore thereof enlarged to form supply and exhaust chambers and a plurality of reservoirs, ofan-` nular partitions between said chambers and said reservoirs respectively, a hollow piston within said cylinder having ports leading from its outer surface to the interior thereof, an enlargement on said piston of a greater length than the length of each of saidl reservoirs whereby said reservoirs are successively connected with said supply-chamber prior to the admission of pressure from said supply-chamber through the ports and hollow interior of said piston to the working end of the cylinder.

9. In a iiuid-pressure-operated tool, the combination with a cylinder having the bore thereof enlarged to form supply and exhaust chambers and a plurality of reservoirs, of an annular partition between said supply and IIO exhaust chambers', a second annular partif tion between said supply-chamber and the adjacent reservoir, a hollow differential piston having a reduced portion fittingA the bore of the first partition and an enlarged portion fitting the bore of the second partition said reduced portion having ports leading to the hollow interior of the piston and said enlarged portion being of a greater length than the length of the reservoirv adjacent to the handle ofv the tool whereby ysaid reservoirs are connected with said supply-chamber prior to the admission of pressure from said supply-chamber through the ports and hollow interior of said piston to the working end of the cylinder. i

IZO

In testimony Awhereof I sign this specifcation in the presence of twowitnesses:

CHARLES HARRIS JOHNSON.

Witnesses:

H. IL'VAUGHAN, B. C. WIEDERHOLD. 

